1. Field of the Invention
This invention relates to an electric connector which electrically connects terminals to each other and electric wires, and more specifically to a connector of a snap-in-fitting system.
The present invention also relates to a unit for covering the connected part between terminals electrically connected by snap-in-fitting and an apparatus for connecting terminals using the same.
The present invention further relates to a storage cell using the electric connector of the snap-in-fitting system mentioned above, a storage module containing a plurality of storage cells connected to each other, and a storage apparatus equipped with a plurality of storage modules.
The present invention further relates to a connection structure of storage cells and a bus bar equipped with the connection structure.
2. Description of the Prior Art
A plug-socket type connector is generally used as a connector which electrically connects the terminals of the storage cells or storage elements to each other and electric wires.
Further, the terminal structure of the fitting type in which a protruded part formed in the terminal of one end of a storage cell body is fitted into a concave portion formed in the terminal of the other end of the other storage cell body has been known as disclosed in published Japanese Utility Model Application, KOKAI (Early Publication) No. (hereinafter referred to briefly as “JUM-A-”) 6-5111, published Japanese Patent Application, KOKAI (Early Publication) No. (hereinafter referred to briefly as “JP-A-”) 2000-123819, and JUM-A-7-36436, for example. According to such terminal structure of the fitting system, it is possible to improve the workability and reduce the production cost because the terminals can be connected by one push operation. However, there is a problem that a large electric current cannot be passed therethrough because the contact surface of terminals cannot be enlarged and a current path thereof is small.
Further, storage cells, such as single cells like a nickel hydrogen cell and a lithium cell, and energy storage elements like an electric double layer capacitor, are used for electric vehicles, hybrid electric vehicles, etc. as a driving power source. For example, as storage power supply unit of an electric vehicle, a storage apparatus called an ultra capacitor has been known. This storage apparatus is equipped with some hundreds of capacitor cells which store or discharge electric power (refer to JP-A-10-125559, for example).
In assembling such an ultra capacitor, since the electric wiring for electrically connecting terminals should be carried out after fixing capacitor cells in the positions close to each other, there is a problem that considerable labor hour and cost will be required for the assembly. For example, in one ultra capacitor, since welding and electric wiring will be performed for about hundreds of capacitor cells, the labor hours and cost required therefor are unfathomable.
Moreover, since the capacitor cells which constitute an ultra capacitor are fixed by a non-detachable fixing method, such as welding, it is impossible to disassemble the ultra capacitor to discrete capacitor cells and to reassemble them. Accordingly, when any fault arises in either of the capacitor cells, all the capacitor cells should be discarded.
Therefore, a method of interposing and fixedly securing a bus bar or a conductor wire, for connecting a plurality of storage cells to each other between a terminal having a male screw part in one end of a storage cell body and a bolt to be fastened thereto has been proposed, as disclosed in JP-A-9-92238, for example. However, according to the technique disclosed in JP-A-9-92238, since the male screw part is thin, a large electric current cannot be passed therethrough. Moreover, since the connection is done by bolting, workability is poor and further the production cost becomes high because a screw part should be formed on the terminal. Further, the terminal structure of the screw type in which a male screw part formed in the terminal of one end of a storage cell body is screwed into a female screw part formed in the terminal of the other end of a storage cell body has been proposed, as disclosed in JP-A-8-222201 and JP-A-2000-77057. However, according to such terminal structure of the screw type, since a screw is fastened onto a male screw part, the workability of connecting storage cells is poor because of the screwing operation and the production cost becomes high because a screw part should be formed on the terminal.
As described above, the conventional connection structure of the storage cells has failed to realize simultaneously all the improved workability, reduction in production cost, and the passing of a large electric current. Such a problem also holds good for the case where a plurality of storage cells are connected to each other by the use of a bus bar.